AY-3-8912 sound chip pinout
DIP-28. Three-voice programmable sound generator with one 8-bit I/O port
Three tone channels, noise and envelope, driven by BDIR, BC1 and BC2; the 28-pin 8912 has only I/O port A. The pin table is generic. Board wiring: on the TS2068 (U14) it sits at ports $F5 (register) and $F6 (data), takes 1.764 MHz from SCLD pin 19, has BC2 and A8 tied to +5 V, mixes A, B and C into one load and reads the joysticks on port A (IOA0-3 directions, IOA7 fire). On the Spectrum 128, +2 and +3 it sits at $FFFD/$BFFD, clocks at 1.7734 MHz and port A drives the keypad/RS-232 socket. A dead AY leaves the beeper working.
Open the interactive AY-3-8912 pinoutPins
| Pin | Name | Type | Signal |
|---|---|---|---|
| 1 | ANALOG C | audio | Channel C D/A output, up to 1 V p-p. |
| 2 | TEST 1 | nc | GI test pin. Leave open. |
| 3 | VCC | power | +5 V supply. |
| 4 | ANALOG B | audio | Channel B D/A output. |
| 5 | ANALOG A | audio | Channel A D/A output. |
| 6 | VSS | ground | Ground. |
| 7 | IOA7 | io | Port A bit 7, on-chip pull-up. |
| 8 | IOA6 | io | Port A bit 6, on-chip pull-up. |
| 9 | IOA5 | io | Port A bit 5, on-chip pull-up. |
| 10 | IOA4 | io | Port A bit 4, on-chip pull-up. |
| 11 | IOA3 | io | Port A bit 3, on-chip pull-up. |
| 12 | IOA2 | io | Port A bit 2, on-chip pull-up. |
| 13 | IOA1 | io | Port A bit 1, on-chip pull-up. |
| 14 | IOA0 | io | Port A bit 0, on-chip pull-up. |
| 15 | CLOCK | clock | Timing reference for tone, noise and envelope. |
| 16 | /RESET | ctrl | LOW clears all registers. On-chip pull-up. |
| 17 | A8 | addr | Extra chip-select address bit, on-chip pull-up; most boards tie it HIGH. |
| 18 | BDIR | ctrl | Bus direction. With BC1 (BC2 HIGH): 0 0 inactive, 0 1 read, 1 0 write, 1 1 latch address. |
| 19 | BC2 | ctrl | Bus control 2; most boards tie it HIGH and drive only BDIR and BC1. |
| 20 | BC1 | ctrl | Bus control 1. |
| 21 | DA7 | data | Data/address bit 7. |
| 22 | DA6 | data | Data/address bit 6. |
| 23 | DA5 | data | Data/address bit 5. |
| 24 | DA4 | data | Data/address bit 4. |
| 25 | DA3 | data | Data/address bit 3. |
| 26 | DA2 | data | Data/address bit 2. |
| 27 | DA1 | data | Data/address bit 1. |
| 28 | DA0 | data | Data/address bit 0. |
Fitted in
- Timex Sinclair 2068 U14
- ZX Spectrum 128 IC32
- ZX Spectrum +2 IC4 (AY-3-8912A)
- ZX Spectrum +3 IC11 (AY-3-8912A)
- Amstrad CPC 464 IC102
- Amstrad CPC 664 IC102
- Amstrad CPC 6128 IC102
- Oric-1 IC4
- Oric Atmos IC4 (verify)